Fix upgrade_tests.py 6 for SVN_WC__NODES_ONLY.
Fix upgrade_tests.py 6 for SVN_WC__NODES_ONLY.

* subversion/tests/cmdline/upgrade_tests.py
  (check_dav_cache): Look at NODES if row not found in BASE_NODE, tweak
   failure message.

jmckaskill/subversion,jmckaskill/subversion,jmckaskill/subversion,jmckaskill/subversion,jmckaskill/subversion,jmckaskill/subversion,jmckaskill/subversion,jmckaskill/subversion